dimensions works on option types
unite_base works on all nulls
isscalar predicate
Merge pull request #96 from mrocklin/discovery-fixes

Discovery fixes
add isscalar to predicates.__all__
Merge branch 'discovery-fixes'
add isunit predicate, improve _dimensions
integers are valid dimensions
add isrecord predicate
add iscollection predicate
rename isunit to isscalar
bump version to 0.3.1
translate readme to rst - better for pypi
fix readme title
bump version to 0.4.0
add predicates isnumeric, isdatelike, isboolean
DataShape launders inputs
Merge pull request #98 from mrocklin/more-predicates

More predicates